Elemental fluorine to 8-fluoropurines in one step

An efficient regiocontrolled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine is described. The one-step procedure produced regiospecific substitution of the C(8)-hydrogen of purine derivatives in isolated yields close to 30% with protected purines in CHCl3. Fluorination yields with unprotected purines in EtOH were reduced to less than 10%. The electrophilic fluorination procedure has a broad scope of applicability and permits a ready and easy access to 8-fluoropurine derivatives, for the first time, for evaluation of their biochemical and pharmacological properties.